Technical Specifications

XL-Class Vibrating Screens

General Information Todays markets have increasingly been demanding higher production rates in form of bigger machines as well as superior machine availability. Traditional shaft driven technology reaches its limitations at a determined width due to the mechanical deflection of the shaft resulting in unacceptable bearing lifetimes. TYCANs solution to the markets demands and the technological limitations of the shaft technology is the exciter driven XL-Class. The exciter is a completely incased drive unit consisting of short shafts supported by closely positioned bearings. Mounted on a specially designed over head bridge the exciter technology allows TYCANs XL-Class to be built at widths up to 14 ft addressing the market need for bigger machines. Due to carefully chosen bearing sizes in combination with maintenance friendly lubrication via oil, the demand for availability is addressed by bearing lifetimes as high as 50,000 hours (application dependant). Although traditionally developed for the mining industries such as copper and iron ore, the XL-Class is finding its way into virtually any application such as sand, crushed stone and aggregates due to its impressive payback and maintenance friendliness. Design Tools XL-Class machines are engineered by integrating finite element analysis (FEA) into the design cycle to ensure the optimum configuration. FEA provides information such as dynamic stress (vibration), natural frequencies and harmonic responses. The FEA presents numerous advantages. A new design concept may be modeled to determine its real world behaviors under various load environments, and may therefore by refined prior to the production process. The final purpose of this analysis is the optimization of vibrating screens components in order to guarantee stress and strain levels that avoid early fatigue failure.

Figure 1 FEA Analysis Models Critical Stresses

Figure 2 Critical Stresses in Screen Panel

Features (Figure 3)

Drive System: Linear Motion Mechanical Oscillators (Exciter units) Drive Transmission System: V-Belts and pulleys or Direct Drive accompanied

with VFD (Variable Frequency Drive) Drive Unit: Electric Motor Bearing lifetime: Up to 50,000 (application dependant) Drive Lubrication: Oil bath Width: 4 to 14 Length: 8 to 36 Decks: Up to 3 max Inclination: -3 to 10 degrees Operating Speed: Adjustable frequency of 750 to 1050 RPM Cut Sizes: to 5 Capacity: Up to 15000 t/h Linear motion exciter provides linear stroke throw Solid HUCK bolted construction Versatility in stroke by weight additions to the exciter counterweight Open construction Protection to/from rotating parts provided by drive guards Structure reinforced with reinforcing plate, reinforcing channels and cross beams

to support large impact and volumes

Figure 3 TYCAN XL Class Features (Application Dependent)

Side Plate/Reinforcing Plate (Figure 4)

high strength carbon steel (ASTM A-36) reinforced in critical areas with additional plates and channels high degree of rigidity due to double bend formed edges ties in all decks to form a more rigid body two body brackets serve as stiffeners in the mounting region of the screen the entire assembly is integrated by the use of highly durable HUCK bolt

construction.

Figure 4 Side Plate Assembly

Screen Panel (Figure 5)

one piece panel HUCKTM-Bolted screen body fastening for extra strength and rigidity two-bend side rail rails available to accommodate suitable media

o flat deck e.g. perforated plate or rubber deck o rails for urethane style panels set up for pin and sleeve arrangement or

rails to accept grooved media o side tensioned media

Finger Deck screen panel (Figure 6) to accommodate Finger Deck media

Figure 5 Screen Panel

Figure 6 Finger Deck Screen Panel

Feed Box (Figure 7)

interchangeable reinforced with gussets accommodates liners to increase life of feed box

Figure 7 Feed Box

Bridge (Figure 8) The main exciter support is a vital part of an XL-Class vibrating machine. The bridge transmits dynamic forces from the exciters through the entire structure. Special design in conjunction with optimum installation location of the bridge assures harmonious operation of the vibrating screen. In addition, the rigid, welded frame also stiffens the upper region of the screen while being HUCK bolted to the side plates. The bridge is complete with machined exciter seats to ensure superior mating of the exciter to the bridge.

Figure 8 Bridge

Drive The motor of the XL-CLASS may need to be mounted outside of the vibrating screen body. In such cases, the motor can be mounted on a Ty-Rider Motorbase (Figure 9). These motor bases provide a self-tensioning base for friction belt drives. Both the pre-tension and the inclination angle can be easily adjusted.

Figure 9 Ty-Rider Motorbase

Benefits of Ty-Rider Motorbases:

automatic compensation of belt elongation which leads to constant, ideal belt tension

slip-free torque transmission easily change belts without pulley realignment reduces wear on bearings, pulleys & belts allows a high degree of deflection which reduces equipment damage

Exciter (Figure 10) Exciter Description

The load bearing capacity of the MU exciter consists of a nodular cast iron casing incorporating the housings for the roller bearings on which the two shafts run. The casing is provided with drilled mounting feet which allow for bolting to the surface placed under vibration. Additionally there are holes for hoisting, handling, and fastening of safety guards. There is access to the inside via the top cover which is fastened by screws.

Figure 10 Exciter

Ground spur gears are keyed on the central part of the shafts. These gears ensure the synchronized counter-rotation of the shafts. The counterweights, which generate the oscillatory straight line movement, are keyed on the shaft outside the bearings.

The load bearing casing also acts as a sump for the oil used in lubricating the

gears and bearings. The inside of the casing is fully coated with oil resistant/ anti-noise paint. The casing is of adequate capacity and shape to ensure lubrication of the various parts for any type of mounting arrangement (horizontal, vertical, inclined). The casing is designed so that the lubricant is picked up by the gears and thrown upwards. The lubricant drops down along the walls and penetrates the bearings. The oil flows through the bearings from the inside to the outside thus lubricating them. It is then conveyed via special oil slinging discs and recycling grooves back to the sump. A tight seal is ensured by a system of multiple mechanical labyrinth seals, with the addition of felts to prevent leakage of lubricant and

infiltration of dust.

The casing is fitted with breather and oil drain plugs (the latter are of the magnetic type) plus the oil fill plug. The exciter is supplied with a dipstick for checking oil level.

The counterweights are drilled with holes for additional steel or lead weights

designed to allow variations in the static moment of the exciter.

All nuts, bolts and screws used are of high strength type (minimum R 80 Kg/mm2 class 8.8)

For the exciter to operate it must be connected to an external motor. Depending

on the weight and dimensions of the vibrating machine it is possible to connect two or more exciters in series. The exciters can be connected with a direct drive and a rubber coupling or with a universal joint drive. A V-Belt pulley drive is used as connection to the electric motor (Figure 11).

Figure 11 Drive Options

Exciter - Principles of Operation (Figure 12) The exciters consist of two counter-rotating shafts whose ends are fitted with two pairs of counterweights. The rotation of the two shafts is synchronized through a pair of gears such as to create linear motion oscillations whose resulting line of force is

perpendicular to the ideal axis of connection of the two shafts.

Figure 12 Resulting Linear Motion of Counter-Rotating Weights

Mounting Options The normal installation position for a horizontal type of screen is at zero degrees and the maximum deviation corresponds to minus 3 degrees and plus 10 degrees. The XL-Class screen comes with two installation options:

1. Floor mounted nests of coil springs used in conjunction with brake unit (Figure 13).

The brake unit is necessary when mounting with coil springs in order to provide lateral stability and control machine movement during start up and shut down.

Figure 13 Coil Springs and Brake Unit

2. Floor mounted with Ty-Rider mounts (Figure 14).

Figure 14 Ty-Rider Mounted XL Class

Ty-Rider Advantage Ty-Rider mounts are offered as an alternative to conventional spring mounting systems. Ty-Rider mounts are based upon the principle of four elastomeric elements inside the base of each oscillating unit. The elements transmit the oscillations of a system, while simultaneously damping vibration, shock, and noise. Due to the unique design, neither shear nor bending stresses occur at the support points, assuring long life.

Figure 15 Double Ty-Rider Configuration

The key features of Ty-Rider mounts that are superior to coil springs are:

Extended life. Lateral stability. Support tensile, compressive and shear stresses. Reduced noise level Prevents excessive and uncontrolled oscillation through start-up and shut down

Vibration Analysis Inspection Every XL-CLASS vibrating machine is backed by years of engineering experience. Prior to shipment each machine is carefully examined and operated over a prolonged period assuring correct balance, satisfactory bearing operating temperatures, smooth operation, acceptable noise levels, and quality workmanship. Each machine is evaluated using a computer vibration analysis tool to find any dynamic irregularities in a vibrating screen. This information makes it possible to view in the monitor the orbit points, peak to peak, median acceleration, displacements, frequency (RPM) and FFT analysis. The combination of speed and stroke on a vibrating screen results in acceleration forces. Operating a screen outside of its proper accelerations reduces screening performance and poses risks to the mechanical integrity of the machine. Measuring the mechanical performance of a vibrating screen builds the basis, minimizing these risks, ensuring proper operation. The healthy screen should display a stable waveform and close to zero acceleration in the side axis.

Figure 16 Vibration Analysis Data Acquisition

Horizontal and vertical vibrations analyzed together allow orbit plots to represent the 2D

shape of the screen motion (Figure 19). This shape also holds valuable information about the condition of the screen. The integrated FFT-analysis separates and analyzes frequency patterns that indicate mechanical problems.

Figure 17 Vibration Analysis Orbit Plots

A software suite processes the information resulting in a report featuring detail information for each measuring point and an evaluation for the entire machine. The summary brief points to modifications that are necessary to achieve optimum performance.